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Abundance and occurrence of mainstream element
Mainstream elements are Hydrogen, Deuterium, Helium, Beryllium, Oxygen, Sulfer, Germanium or Copper, and Gadolinium or in elemental periodic table. Occurrence of Sulfur , a volcano in East Java, Indonesia (photo 2009)]] Elemental sulfur can be found near hot springs and volcanic regions in many parts of the world, especially along the Pacific Ring of Fire. Such volcanic deposits are currently mined in Indonesia, Chile, and Japan. Sicily is also famous for its sulfur mines. Sulfur deposits are polycrystalline, and the largest documented single crystal measured 22×16×11 cm3. Significant deposits of elemental sulfur also exist in salt domes along the coast of the Gulf of Mexico, and in evaporites in eastern Europe and western Asia. The sulfur in these deposits is believed to come from the action of anaerobic bacteria on sulfate minerals, especially gypsum, although apparently native sulfur may be produced by geological processes alone, without the aid of living organisms (see below). However, fossil-based sulfur deposits from salt domes are the basis for commercial production in the United States, Poland, Russia, Turkmenistan, and Ukraine. , stockpiled for shipment in North Vancouver, B.C.]] Sulfur production through hydrodesulfurization of oil, gas, and the Athabasca Oil Sands has produced a surplus ? huge stockpiles of sulfur now exist throughout Alberta, Canada. Common naturally occurring sulfur compounds include the sulfide minerals, such as pyrite (iron sulfide), cinnabar (mercury sulfide), galena (lead sulfide), sphalerite (zinc sulfide) and stibnite (antimony sulfide); and the sulfates, such as gypsum (calcium sulfate), alunite (potassium aluminium sulfate), and barite (barium sulfate). It occurs naturally in volcanic emissions, such as from hydrothermal vents, and from bacterial action on decaying sulfur-containing organic matter. The distinctive colors of Jupiter's volcanic moon, Io, are from various forms of molten, solid and gaseous sulfur. There is also a dark area near the Lunar crater Aristarchus that may be a sulfur deposit. Sulfur is present in many types of meteorites. Ordinary chondrites contain on average 2.1% sulfur, and carbonaceous chondrites may contain as much as 6.6%. Sulfur in meteorites is normally present as troilite (FeS), but other sulfides are found in some meteorites, and carbonaceous chondrites contain free sulfur, sulfates, and possibly other sulfur compounds. Natural abundance of Deuterium Deuterium occurs in trace amounts naturally as deuterium gas, written ²H2 or D2, but most natural occurrence in the universe is bonded with a typical ¹H atom, a gas called hydrogen deuteride (HD or ¹H²H). The existence of deuterium on Earth, elsewhere in the solar system (as confirmed by planetary probes), and in the spectra of stars, is an important datum in cosmology. Stellar fusion destroys deuterium, and there are no known natural processes (for example, see the rare cluster decay), other than the Big Bang nucleosynthesis, which might have produced deuterium at anything close to the observed natural abundance of deuterium. This abundance seems to be a very similar fraction of hydrogen, wherever hydrogen is found. Thus, the existence of deuterium is one of the arguments in favor of the Big Bang theory over the steady state theory of the universe. It is estimated that the abundances of deuterium have not evolved significantly since their production about 13.7 billion years ago.The End of Cosmology?: Scientific American The world's leading "producer" of deuterium (technically, merely enricher or concentrator of deuterium) was Canada, until 1997 when the last plant was shut down (see more in the heavy water article). Canada uses heavy water as a neutron moderator for the operation of the CANDU reactor design. India is now probably the world's largest concentrator of heavy water, also used in nuclear power reactors. Production of Heavy water On Earth, semiheavy water, HDO, occurs naturally in regular water at a proportion of about 1 molecule in 3200. This means that 1 in 6400 hydrogen atoms is deuterium, which is 1 part in 3200 by weight (hydrogen weight). The HDO may be separated from regular water by distillation or electrolysis and also by various chemical exchange processes, all of which exploit a kinetic isotope effect. (For more information about the isotopic distribution of deuterium in water, see Vienna Standard Mean Ocean Water.) The difference in mass between the two hydrogen isotopes translates into a difference in the zero-point energy and thus into a slight difference in the speed at which the reaction proceeds. Once HDO becomes a significant fraction of the water, heavy water will become more prevalent as water molecules trade hydrogen atoms very frequently. To produce pure heavy water by distillation or electrolysis requires a large cascade of stills or electrolysis chambers, and consumes large amounts of power, so the chemical methods are generally preferred. The most important chemical method is the Girdler sulfide process. An alternative processMethod for isotope replenishment in an exchange liquid used in a laser, patented by Graham M. Keyser, uses lasers to selectively dissociate deuterated hydrofluorocarbons to form deuterium fluoride, which can then be separated by physical means. Although the energy consumption for this process is much less than for the Girdler sulfide process, this method is currently uneconomical due to the expense of procuring the necessary hydrofluorocarbons. Natural abundance of Helium Helium is the second most abundant element in the known Universe (after hydrogen), constituting 23% of the baryonic mass of the Universe. The vast majority of helium was formed by Big Bang nucleosynthesis one to three minutes after the Big Bang. As such, measurements of its abundance contribute to cosmological models. In stars, it is formed by the nuclear fusion of hydrogen in proton-proton chain reactions and the CNO cycle, part of stellar nucleosynthesis. ; In the Earth's atmosphere, the concentration of helium by volume is only 5.2 parts per million. The concentration is low and fairly constant despite the continuous production of new helium because most helium in the Earth's atmosphere escapes into space by several processes. In the Earth's heterosphere, a part of the upper atmosphere, helium and other lighter gases are the most abundant elements. Nearly all helium on Earth is a result of radioactive decay, and thus an Earthly helium balloon is essentially a bag of retired alpha particles. Helium is found in large amounts in minerals of uranium and thorium, including cleveite, pitchblende, carnotite and monazite, because they emit alpha particles (helium nuclei, He2+) to which electrons immediately combine as soon as the particle is stopped by the rock. In this way an estimated 3000 metric tons of helium are generated per year throughout the lithosphere. In the Earth's crust, the concentration of helium is 8 parts per billion. In seawater, the concentration is only 4 parts per trillion. There are also small amounts in mineral springs, volcanic gas, and meteoric iron. Because helium is trapped in a similar way by non-permeable layer of rock like natural gas the greatest concentrations on the planet are found in natural gas, from which most commercial helium is derived. The concentration varies in a broad range from a few ppm up to over 7% in a small gas field in San Juan County, New Mexico. Occurrence of Beryllium The beryllium concentration of the Earth's surface rocks is ca. 4–6 ppm. Beryllium is a constituent of about 100 out of about 4000 known minerals, the most important of which are bertrandite (Be4Si2O7(OH)2), beryl (Al2Be3Si6O18), chrysoberyl (Al2BeO4), and phenakite (Be2SiO4). Precious forms of beryl are aquamarine, bixbite(beryllium aluminium cyclosilicate with the chemical formula Be3Al2(SiO3)6) and emerald(a variety of the mineral beryl (Be3Al2(SiO3)6,) colored green by trace amounts of chromium and sometimes vanadium). Deposits of Beryl Beryl of various colors is found most commonly in granitic pegmatites, but also occurs in mica schists in the Ural Mountains, and limestone in Colombia. Beryl is often associated with tin and tungsten ore bodies. Beryl is found in Europe in Norway, Austria, Germany, Sweden (especially morganite), and Ireland, as well as Brazil, Colombia, Madagascar, Russia, South Africa, the United States, and Zambia. U.S. beryl locations are in California, Colorado, Idaho, Maine, Connecticut, New Hampshire, North Carolina, South Dakota, and Utah. New England's pegmatites have produced some of the largest beryls found, including one massive crystal from the Bumpus Quarry in Albany, Maine with dimensions 5.5 m by 1.2 m (18 ft by 4 ft) with a mass of around 18 metric tons; it is New Hampshire's state mineral. As of 1999, the largest known crystal of any mineral in the world is a crystal of beryl from Madagascar, 18 meters long and 3.5 meters in diameter.G. Cressey and I. F. Mercer, Crystals, London, Natural History Museum, 1999 Occurrence of Copper Copper can be found as native copper in mineral form (for example, in Michigan's Keewenaw Peninsula). It is a polycrystal, with the largest single crystals measuring 4.4×3.2×3.2 cm. Minerals such as the sulfides: chalcopyrite (CuFeS2), bornite (Cu5FeS4), covellite (CuS), chalcocite (Cu2S) are sources of copper, as are the carbonates: azurite (Cu3(CO3)2(OH)2) and malachite (Cu2CO3(OH)2) and the oxide: cuprite (Cu2O). Natural abundance of Germanium Germanium is created through stellar nucleosynthesis, mostly by the s-process in asymptotic giant branch stars. The s-process is a slow neutron capture of lighter elements inside pulsating red giant stars. Germanium has been detected in the atmosphere of Jupiter and in some of the most distant stars. Its abundance in the Earth's crust is approximately 1.6 ppm. There are only a few minerals like argyrodite(silver germanium sulfide Ag8GeS6), briartite(opaque iron-grey metallic sulfide mineral, Cu2(Zn,Fe)GeS4 ), germanite(copper iron germanium sulfide mineral, Cu26Fe4Ge4S32), and renierite((Cu,Zn)11(Ge,As)2Fe4S16 is a rare copper zinc germanium bearing sulfide mineral) that contain appreciable amounts of germanium, but no minable deposits exist for any of them. Nonetheless, none is mined for its germanium content. Some zinc-copper-lead ore bodies contain enough germanium that it can be extracted from the final ore concentrate. An unusual enrichment process causes a high content of germanium in some coal seams, which was discovered by Victor Moritz Goldschmidt during a broad survey for germanium deposits. The highest concentration ever found was in the Hartley coal ash with up to 1.6% of germanium. The coal deposits near Xilinhaote, Inner Mongolia, contain an estimated 1600 tonnes of germanium. See also *sulfide of iron *sulfide of copper *sulfide of mercury References ko:주류 원소 Category:gravity wikia Category:stream elements